5.a Palkert Variance - Comments from Watershed 11.27.19From: Mike Isensee <mike.isensee@cmscwd.org>
Sent: Wednesday, November 27, 2019 11:07 AM
To: Merritt Clapp-Smith <merritt.clapp-smith@tkda.com>; Sorensen, Jenifer (DNR)
<jenifer.sorensen@state.mn.us>
Cc: Carl Almer <calmer@eorinc.com>
Subject: RE: Review Palkert home plan for Big Marine Lake
Hello Merritt,
Thank you for the opportunity to review and comment on the proposed single-family residence
riparian to Big Marine Lake located at 12632 182nd Street North.
Big Marine Lake is a high-quality recreational lake and identified as a priority resource of the
District with 328 shoreland parcels and classified as a groundwater-dependent natural
resource. Over the last thirty years the District and City have worked collaboratively with
landowners to protect and enhance buffers, water quality, and habitat of Big Marine Lake
through voluntary conservation practices and regulations triggered by new and redevelopment.
As such the required buffer on Big Marine Lake is 100-feet from the OHWL. Due to exemption
4.9.4, the regulated buffer for the complete reconstruction and expansion of impervious surface
of this site is diminished, however the intent (and common goal) to keep the shoreland area free
of structures still exists.
Therefore, the District does not support retaining walls parallel with, and within the shoreland
area of Big Marine Lake. The proposed retaining wall is prohibited within a new development
scenario and is averse to the goals of providing the greatest possible protection to buffers, water
quality, and habitat of Big Marine Lake.
The following District rules may also apply:
• Rule 2 Stormwater Management – 6,507 SF of impervious is proposed. Rule 2.2(c) is
applicable and requires 976 cubic feet of BMP storage to capture and treat stormwater
from impervious surfaces. A declaration for maintenance of stormwater facilities will be
required to be recorded for implemented BMPs.
• Rule 3 Erosion & Sediment Control – Rule 3.2(c) is applicable and requires standard
erosion and sediment control measures such as a rock construction entrance, silt fence or
logs downslope of all disturbed areas, protection of stormwater BMPs during
construction, revegetation specifications, etc.
• Rule 4 Buffers – Is applicable if the structure setback variance from the OHWL of Big
Marine or the impervious surface percentage is approved. A buffer will be required to be
established with native vegetation for areas disturbed within the required buffer area. A
buffer declaration will be required to be recorded and the buffer area will need to be
monument. The standard buffer width for Big Marine Lake is 100-feet from the OHWL
as it is a Groundwater-Dependent Natural Resource. However, it appears that the 16.1-ft
buffer width proposed complies with District Rules, if the setback variance is approved,
considering Exception 4.9.4 – a buffer width of 50% of the existing structure setback
(32.2-ft).
• Rule 5 –If shoreline alterations are proposed, bioengineering must be used for
stabilization unless demonstrated infeasible.
• Rule 7 – There does not appear to be floodplain fill (fill below 942.5). Low floor must be
at least 944.5.
Thank you again for the opportunity to provide these comments. Please contact me if you have
any questions.
Regards,
Mike
Mikael Isensee, CPESC
Administrator | Carnelian Marine St. Croix Watershed District
21150 Ozark Ave N | Scandia, MN 55073 | ( (651) 433-2150
Cell: 612-839-6492 : www.cmscwd.org